I have a four zone oil hot water baseboard heating system and an oil hot water heater. I have always wondered if these electric point of use water heater units might be a viable replacement. It may sound crazy but could I have a point of use unit added to each zone and tap into the pump electrical contact? Then when the thermostat says send hot water through the pipes, the pump would go on and the point of use unit would begin to heat the water on the way to the radiators.

Would this work as a replacement for the hot water heater, too? Could I put point of use units on each hot water line and eliminate my water heater altogether?

I must be missing soemthing, or this idea would be all over the place as oil prices skyrocket.